Package org.axonframework.eventhandling

Class SubscribingEventProcessor

java.lang.Object

org.axonframework.eventhandling.AbstractEventProcessor

org.axonframework.eventhandling.SubscribingEventProcessor

All Implemented Interfaces:

EventProcessor, Lifecycle, MessageHandlerInterceptorSupport<EventMessage<?>>

public class SubscribingEventProcessor
extends AbstractEventProcessor
implements Lifecycle

Event processor implementation that subscribes to the EventBus for events. Events published on the event bus are supplied to this processor in the publishing thread.

Depending on the given EventProcessingStrategy the events are processed directly (in the publishing thread) or asynchronously.

Since:

3.0

Author:

Rene de Waele

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	SubscribingEventProcessor.Builder	Builder class to instantiate a SubscribingEventProcessor.

Nested classes/interfaces inherited from interface org.axonframework.lifecycle.Lifecycle

Lifecycle.LifecycleHandler, Lifecycle.LifecycleRegistry

Field Summary

Fields inherited from class org.axonframework.eventhandling.AbstractEventProcessor

spanFactory

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	SubscribingEventProcessor(SubscribingEventProcessor.Builder builder)	Instantiate a SubscribingEventProcessor based on the fields contained in the SubscribingEventProcessor.Builder.

Method Summary

Modifier and Type	Method	Description
static SubscribingEventProcessor.Builder	builder()	Instantiate a Builder to be able to create a SubscribingEventProcessor.
SubscribableMessageSource<? extends EventMessage<?>>	getMessageSource()	Returns the message source from which this processor receives its events
boolean	isError()	Indicates whether the processor has been shut down due to an error.
boolean	isRunning()	Indicates whether this processor is currently running (i.e. consuming events from its message source).
protected void	process(List<? extends EventMessage<?>> eventMessages)	Process the given messages.
void	registerLifecycleHandlers(Lifecycle.LifecycleRegistry handle)	Registers the activities to be executed in the various phases of an application's lifecycle.
void	shutDown()	Shut down this processor.
void	start()	Start this processor.

Methods inherited from class org.axonframework.eventhandling.AbstractEventProcessor

canHandle, canHandleType, eventHandlerInvoker, getHandlerInterceptors, getName, processInUnitOfWork, processInUnitOfWork, registerHandlerInterceptor, reportIgnored, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.axonframework.eventhandling.EventProcessor

shutdownAsync

Constructor Details

SubscribingEventProcessor

protected SubscribingEventProcessor(SubscribingEventProcessor.Builder builder)

Instantiate a SubscribingEventProcessor based on the fields contained in the SubscribingEventProcessor.Builder.

Will assert that the Event Processor name, EventHandlerInvoker and SubscribableMessageSource are not null, and will throw an AxonConfigurationException if any of them is null.

Parameters:

builder - the SubscribingEventProcessor.Builder used to instantiate a SubscribingEventProcessor instance

Method Details

builder

public static SubscribingEventProcessor.Builder builder()

Instantiate a Builder to be able to create a SubscribingEventProcessor.

The RollbackConfigurationType defaults to a RollbackConfigurationType.ANY_THROWABLE, the ErrorHandler is defaulted to a PropagatingErrorHandler, the MessageMonitor defaults to a NoOpMessageMonitor, the EventProcessingStrategy defaults to a DirectEventProcessingStrategy, the EventProcessorSpanFactory defaults to a DefaultEventProcessorSpanFactory backed by a NoOpSpanFactory, and the TransactionManager defaults to the NoTransactionManager.INSTANCE. The Event Processor name, EventHandlerInvoker and SubscribableMessageSource are hard requirements and as such should be provided.

Returns:

a Builder to be able to create a SubscribingEventProcessor

registerLifecycleHandlers

public void registerLifecycleHandlers(@Nonnull
 Lifecycle.LifecycleRegistry handle)

Description copied from interface: Lifecycle

Registers the activities to be executed in the various phases of an application's lifecycle. This could either be at startup, shutdown, or both.

Specified by:

registerLifecycleHandlers in interface Lifecycle

Parameters:

handle - the lifecycle instance to register the handlers with

See Also:

• Lifecycle.LifecycleRegistry.onShutdown(int, Runnable)
• Lifecycle.LifecycleRegistry.onShutdown(int, LifecycleHandler)
• Lifecycle.LifecycleRegistry.onStart(int, Runnable)
• Lifecycle.LifecycleRegistry.onStart(int, LifecycleHandler)

start

public void start()

Start this processor. This will register the processor with the EventBus.

Upon start up of an application, this method will be invoked in the Phase.LOCAL_MESSAGE_HANDLER_REGISTRATIONS phase.

Specified by:

start in interface EventProcessor

isRunning

public boolean isRunning()

Description copied from interface: EventProcessor

Indicates whether this processor is currently running (i.e. consuming events from its message source).

Specified by:

isRunning in interface EventProcessor

Returns:

true when running, otherwise false

isError

public boolean isError()

Description copied from interface: EventProcessor

Indicates whether the processor has been shut down due to an error. In such case, the processor has forcefully shut down, as it wasn't able to automatically recover.

Note that this method returns false when the processor was stopped using EventProcessor.shutDown().

Specified by:

isError in interface EventProcessor

Returns:

true when paused due to an error, otherwise false

process

protected void process(List<? extends EventMessage<?>> eventMessages)

Process the given messages. A Unit of Work must be created for this processing.

This implementation first filters the given eventMessages to only include messages that can be handled by the configured EventHandlerInvoker. Messages that cannot be handled are reported as ignored via AbstractEventProcessor.reportIgnored(EventMessage), notifying any configured MessageMonitor.

If there are messages that can be handled, a BatchingUnitOfWork is created for the filtered batch and processing is delegated to it.

Parameters:

eventMessages - The messages to process.

shutDown

public void shutDown()

Shut down this processor. This will deregister the processor with the EventBus.

Upon shutdown of an application, this method will be invoked in the Phase.LOCAL_MESSAGE_HANDLER_REGISTRATIONS phase.

Specified by:

shutDown in interface EventProcessor

getMessageSource

public SubscribableMessageSource<? extends EventMessage<?>> getMessageSource()

Returns the message source from which this processor receives its events

Returns:

the MessageSource from which the processor receives its events